The present invention relates to side rails disposed above the deck on one lateral side for preventing the bedding such as a bed quilt and a user such as a patient from falling, particularly a lifting mechanism for liftable side rails, in which side rails can be lifted and lowered between the service position above the deck and the stored position below the deck.
The conventional side rails to be disposed above the deck on one lateral side of a lying table such as a bed or stretcher include, as described later, a detachable side rail consisting of a side rail proper and columns which are inserted into the fitting holes formed in a lateral side of the deck, for supporting the side rail proper in its service condition, and a liftable side rail in which a side rail proper is supported liftably by any proper lifting mechanism, to be used at a lifted position and to be stored at a lowered position for avoiding any disturbance by the top of the side rail proper. They also include an full side rail to cover an entire lateral side of a lying table, and a partial side rail to cover an entire lateral side of a lying table in combination with other side rails, usually another side rail.
As an example of lying tables, medical beds are being specified in dimensions of respective portions by standards to allow their safe use. For example, for partial side rails, for example, IEC specifies the dimensions of respective portions as described below in reference to FIG. 8.
The components of FIG. 8 will be explained at first. Symbol 1 denotes the deck of a bed, and the deck 1 is liftably supported above a base 2 by any proper link mechanism 3, and can be driven to be lifted and lowered by a drive mechanism not illustrated. Symbol 4 denotes a partial side rail which is supported by any proper support mechanism at one lateral side of the deck 1 in its service condition. Two such partial side rails 4 are installed side by side, to cover the entire lateral side of the deck 1. Each of the partial side rails consists of a side rail proper 5 and columns 6 which are inserted into the fitting holes (not illustrated) formed in a lateral side of the deck 1. As for other illustrated components, symbol 7 denotes a mattress placed on the deck 1; 8, a head board; and 9, a foot board.
The specified dimensions of the respective portions shown in FIG. 8 are described below.
The dimension indicated by A shows the dimension of each closed space formed in the side rail proper 5 of the side rail 4, when the side rail proper 5 is a lattice with spaces in it. The dimension of each space is specified to be 120 mm or less, to prevent that the head of the user enters into the space.
The dimension indicated by D is the dimension of the gap between the side rails proper 5 of the adjacent side rails 4, or the dimension of the gap between the side rail proper 5 on the head board side and the head board 8 or between the side rail proper 5 on the foot board side and the foot board 9. The dimension of any of the gaps is specified to be 60 mm or less to prevent that the neck of the user enters into the gap, or to be 235 mm or more, to prevent that the head is caught in the gap.
The dimension indicated by F is the dimension of the gap between the bottoms of the side rails proper 5 and the deck 1 when there is an open space above the gap. The dimension of the gap is specified to be 120 mm or less to prevent that the head enters into the gap when the neck cannot enter into the above opening, or to be 60 mm or less to prevent that the neck goes into the gap below the side rails proper 5 when the neck can enter into the above opening.
G1 and G2 indicate the horizontal lengths of the side rails proper 5 of the respective side rails 4, and are specified to satisfy a formula of G1+G2 greater than L/2, where L is the total length L of the deck 1.
The dimension indicated by H is the height of the side rails proper 5 of the side rails 4, i.e., the dimension between the upper surface of the mattress 8 and the tops of the side rails proper of the side rails 4, being specified to be 220 mm or more.
The dimensions of respective portions of the partial side rails described above are applied also when liftable side rails proper are used at a lifted position.
A conventional example of liftable side rails, particularly partial side rails is described below in reference to FIG. 9.
In FIG. 9, symbol 11 generally denotes a bed equipped with liftable side rails. In this drawing, the detailed structure of the bed is not illustrated, and some components only are indicated by two-dot-dash lines.
Symbol 12 denotes a deck to have a mattress (not illustrated) placed on it, and the deck 12 is divided into four deck portions, i.e., four deck portions 12a, 12b, 12c and 12d respectively corresponding to the back, waist, thigh and legs of the user. They are respectively connected to allow pivotal rotation. The deck 12 consisting of these deck portions is supported above a deck support frame 13. Particularly, at first, the deck portion 12b is stationarily supported on the deck support frame 13. The deck portions 12a and 12c are pivotally rotatably connected with the deck portion 12b as described above, and pivotally rotatably and liftably supported by boost arms 14a and 14c which are components of a drive mechanism (not illustrated). Said support mechanism and drive mechanism are not illustrated, since they are well-known.
The deck support frame 13 is supported by any appropriate support mechanism on the floor 15 of a room, etc. The support mechanism is not illustrated. For example, the deck support frame 13 can be supported at a predetermined height by stands or can be liftably supported by a lifting link mechanism above a base as shown in FIG. 8. In FIG. 9, symbol 16 denotes a head board, and 17, a foot board.
On the head board side and the foot board side of the deck support frame 13, respectively one pair of support arms 18a and 18b are supported pivotally rotatably around the rotary shafts extending in the transverse direction of the bed. At the tips of the pair of support arms 18a and 18b, side rails proper 19a and 19b are pivotally rotatably connected, to form a parallel motion link mechanism. The support arms 18a and 18b can also be pivotally rotatably supported on the deck portions 12a, 12c, etc., not on the deck support frame 13.
In the above constitution, the side rails proper 19a and 19b are lifted and lowered by the pivotally rotational motion of the support arms 18a and 18b in parallel along the pivotally rotational loci. The condition that they are held at a lowered position is the stored condition, and the condition where they are held at a lifted position is the service condition. The side rails proper 19a and 19b are schematically drawn by their outer frames only, but have components such as lattice members to satisfy the above mentioned standard dimensions, and though the holding mechanism for the service condition and the stored condition is not illustrated, any well-known adequate mechanism can be used.
As described above, the liftable side rails, the side rails proper of which are liftably supported by any proper lifting mechanism in the service condition at the lifted service position and also in the stored condition at the lowered stored position, must conform to the standard dimensions as described above in the service condition. However, also in the stored condition, there are desirable dimensions in view of convenience. That is, in the use of the bed shown in FIG. 9. when the side rails are held at the stored position, it can happen that an attendant nurses the user such as a patient lying on the bed, or that the table plate of a movable bed side table is moved and located above the bed. In the former case, it can happen that the attendant inserts his/her legs into the gap formed between the bottoms of the side rails proper in the stored condition and the floor 15 of the sickroom, etc., and in the latter case, the base of the bed side table is moved inside the gap. So, it is desirable that the gap h is larger.
On the other hand, recently there is a tendency to keep the bed deck height low, because of various advantages that the user such as a patient can easily get on and off the bed deck and sit at the edge of the deck 12 and that the attendant can more easily nurse if the bed is low in deck height.
In the liftable side rails, the side rails proper of which can be lifted and lowered in parallel by the pivotal rotation of the support arms, it is a contradictory challenge to keep the bed deck height low, while keeping the distance h between the bottoms of the side rails proper and the floor surface large.
The reason is that, if it is attempted to keep the distance h between the bottoms of the side rails proper and the floor surface large while keeping the height H of the side rails proper shown in FIG. 8 sufficiently high (this is necessary for safety), the positions where the support arms are fixed, hence the position of the bed deck must be kept high.
So, hitherto, these dimensions are set considering the above mentioned contradictory challenge, and it is very difficult to keep the distance h between the bottoms of the side rails proper and the floor surface large while keeping the bed deck height low and keeping the height H of the side rails proper sufficiently high.
This invention has been conceived in view of the above. The object of this invention is to provide a lifting mechanism for liftable side rails, in which the side rails proper thereof can be lifted and lowered by the pivotal rotation of support arms along the pivotally rotational loci, characterized by allowing the height H of the side rails proper to be kept sufficiently high at the service position while allowing the distance h between the bottoms of the side rails proper and the floor surface to be kept large at the stored position.
This object can be achieved by a lifting mechanism for side rails, comprising each of the side rails proper, consisting of a plurality of vertically disposed side rail members, the plurality of side rail members, being pivotally rotatably connected, on the respectively both horizontal sides thereof, with a pair of support arms pivotally rotatably supported at side rail installation points of the lying table such as a bed, to be supported in such a manner that the side rail members may be lifted and lowered by the pivotally rotational motion of these support arms along the pivotally rotational loci, and the connection points between the support arms and the side rail members, being disposed in such a manner that the connection points of the upper side rail member make pivotally rotational motion relatively delayed in phase, with the connection points of the lowest side rail member as the fulcrums, when the side rail members are moved to descend by the pivotally rotational motion of the support arms.
In this lifting mechanism for side rails, the pair of support arms connected with the respectively horizontal both sides of the plural side rail members lift and lower the side rail proper consisting of a plurality of side rail members by the pivotal rotation of the support arms along the pivotally rotational loci between the high service position and the low stored position.
In this motion, the connection points between the support arms and the side rail members are disposed in such a manner that the connection points of the upper side rail member make pivotally rotational motion relatively delayed in phase, with the connection points of the lowest side rail member as the fulcrums, when the side rail members are moved to descend by the pivotally rotational motion of the support arms. Therefore, the pivotally rotational stroke of the support arms free from the mutual interference of the respective components of the mechanism, hence the lifting stroke of the lowest side rail member can be made large to allow the stored position and the service position to be disposed preferably.
Furthermore, since the side rail proper consisting of vertically disposed plural side rail members becomes smaller in the vertical height at the low stored position than at the high service position, the distance between the bottom of the side rail and the floor surface at the stored position can be kept large while keeping the bed deck height low and keeping vertical height at the service position sufficiently high.
In this lifting mechanism for side rails, the connection points between the respective side rail members and the support arms can be disposed in such a manner that the distances between the respective connection points in the vertical direction become longest during the descending motion of the side rail members by the pivotally rotational motion of the support arms.
In this constitution, the distance between the respective side rail members does not monotonously become large in the motion from the stored position to the service position, but becomes maximum during the motion and becomes a little smaller again. So, it can be prevented that the gap between the respective side rail members becomes too large at the service position.
In the above side rail support mechanism, it is preferable in the application of this invention, that the plurality of side rail members are connected with the support arms, to form a parallel motion link mechanism. However, it is not necessarily required to form a perfect parallel motion link mechanism, and an adequately shifted four-node link mechanism can also be adopted.
Furthermore, in the above side rail support mechanism, the side rail can consist of vertically disposed two side rail members, and the lower side rail member can have an outside form of being smaller in vertical height on the front side of the descending motion, than on the rear side, and having a step to make a vertically extended portion at the top on the rear side, while the upper side rail member can have an external form of being larger in vertical height on the front side than on the rear side, and having a step to make a vertically extended portion at the bottom on the rear side.
In this constitution, at the service position, the lower side rail member and the upper side rail member can be disposed with a predetermined distance kept between them, while the front side and the rear side of the lower side rail member face the front side and the rear side of the upper side rail member, and therefore, the vertical height of the side rail proper can be kept large. Furthermore, at the stored position, the lower side rail member and the upper side rail member can be disposed with a predetermined distance kept between them, while the front side of the lower side rail member faces the rear side of the upper side rail member, and therefore, the vertical height of the side rail proper can be kept small.
Moreover, the side rail can consist of three or more rail-shaped side rail members, and in this case, a connecting link can be connected between the intermediate points of the rail-shaped side rail members, to form a parallel motion link mechanism.
In the above lifting mechanism for side rails, the support arms can be connected at the ends of the respective side rail members.
In this constitution, since an upwardly open space is not formed below the side rails proper, it is not necessary to consider the dimension indicated by F of FIG. 8 described in the explanation of a standard for the dimensions of side rails.
Furthermore, in the lifting mechanism for side rails, each of the support arms can be a bent link, in which, from the tip of a first arm portion extending from the side rail installing point of the lying table such as a bed to the lowest side rail member, a second arm portion can be protruded toward the rear side of the descending motion. Each of the support arms can also be formed by a plate free from any bent portion.
In the above lifting mechanism for side rails, two side rails can be provided on front and rear sides at one lateral side of the lying table such as a bed, to cover the lateral side entirely, or one side rail can be provided to cover the lateral side entirely.
In the former partial side rails, the side rails on the front and rear sides can be lowered to keep the side rails proper thereof stored near the ends of the lying table such as a bed.